Again, the forums are the proper place for general questions like this. The issue tracker is primarily for reporting bugs. But to answer your question, copyright laws differ from country to country, so the answer is "it depends". In the US, anything written before 1923 is now public domain, as are some but not all pieces written in the years shortly after that. If a piece is still copyrighted, you can certainly create your own arrangement, but if you post it to musescore, you should mark it "private" and then share it only as widely as the laws of your country allow.
Comments
Oops... made a mistake. After I write the sheet music can I post it on musescore so every one can see it?
Again, the forums are the proper place for general questions like this. The issue tracker is primarily for reporting bugs. But to answer your question, copyright laws differ from country to country, so the answer is "it depends". In the US, anything written before 1923 is now public domain, as are some but not all pieces written in the years shortly after that. If a piece is still copyrighted, you can certainly create your own arrangement, but if you post it to musescore, you should mark it "private" and then share it only as widely as the laws of your country allow.